WHEN WAS REVELATION WRITTEN?

Evidence for the early date: 70 A.D.

The many "coming soon" and "at hand" passages (1:1, 2:16, 3:11, 22:6-20) only make sense if events matching the symbolism of Revelation were not too far in the future. The Jewish themes would make no sense after 70 A.D. - there was nothing left of the Jewish state.
The Beast (which most if not all scholars agree represents Rome) was ruled by its 6th head ("head" = "king" see: 17:10) which was already in existence in John's day. Of the 7 heads (kings) only one was left - by 95 A.D. Rome was long past its 7th Caesar.
A 2nd Century manuscript of Revelation says it was written when Nero was Caesar (68 A.D.).
There were still Judaizers in the church at that time (Rev. 2:9, 3:9) - impossible after 70A.D.
The temple is apparently still standing in chapter 11.
If the temple had already been destroyed, one would expect at least one mention of it somewhere.
Revelation 2:2 shows that there were other apostles around - yet it is believed that all but John were dead by 70 A.D.
Irenaeus' statement regarding Domitian's reign is difficult to interpret and based on a secondary source. In the same passage he also mentions "ancient copies" of Revelation in existence which makes little sense if they were only a few years old.
Evidence for a massive persecution by Domitian (81-96 A.D.) is lacking.
The only time there were only 7 churches in Asia was the early 60's.
John was told he must prophesy again before kings (10:11) . . . he would have been over 90 if the late date is correct. Stories of his actions after being released from Patmos are difficult to reconcile with an aged man.